Queensland HealthQueensland Clinical Guidelinesshort GUIDERh D negative women and pregnancyIMPORTANT:Consider individual clinical circumstances.Consult a pharmacopeia for complete drug information.Readthe full disclaimer at www.health.qld.gov.aw/qcgIntroductionAspectConsiderationEarly pregnancy screening,recognition of risk and timely management reduces incidence of fetaldeath and adverse neonatal outcomesContextRh D negative women are at risk of alloimmunisation that may affect future pregnancies2In Australia,approximately 15%of Australians are Rh D negative3.4Alloimmunisation:immune system response of Rh D negative woman to Rh D positive fetal redcells expressing the Rh D antigen2.点，sAnti-D antibody:circulating RhD antibodieso Passive antibodies are acquired from an external source (e.g.Rh D immunoglobulin(Ig))0Preformed antibodies are acquired when Rh D negative woman is exposed to Rh D positivered cells and develops antibodies (sensitising event)Direct antiglobulin test(DAT):determines whether there is binding of maternal immunoglobulinantibodies(Rh D antibodies)to baby's red cell antigens?(known historically as direct Coombstest(DCT))Flow cytometry:most accurate and method of choice for quantification of feto-maternalhaemorrhage(FMH)8Haemolytic disease of the fetus and newborn(HDFN):maternal lg G antibodies are causingDefinitionsdestruction of baby's red cells,and if severe can cause anaemia and hydropsKleihauer-Betke test:detects and quantifies FMH8NIPA:non-invasive prenatal analysis for fetal RHD gene used to predict the baby's Rh D status(also referred to as NIPT (non-invasive prenatal test)by National Blood Authority)Rh DIg:the product administered to Rh D negative woman with no preformed anti-D antibodiessRh D positive or negative:blood groupe(if positive the D antigen is present on red cells)Rh D(previously known as Rhesus)positive person:carries D antigen on their red cells 10Rh incompatibility:mother and fetus incompatible for Rh D groupRHD:name given to the gene that encodes Rh D blood group,and used to refer to the genotypein the fetus determined by non-invasive prenatal test to analyse cell-free fetal DNA in maternalbloode.11.12Woman/women:in Queensland Clinical Guideline(QCG)documents,the terms woman andwomen includes people who do not identify as women but who are pregnant or have given birthPathogenesis of alloimmunisation2:o D antigen is expressed on fetal red cells by 38 days of gestation in Rh D positive fetuso If maternal alloimmunisation occurs as a result of sensitising event,anti-D IgG antibodiescross the placenta and may result in fetal anaemia in the Rh D positive fetus in subsequentpregnancies-may also be caused by incompatible blood transfusion (rare)Outcome from alloimmunisation:Alloimmunisation0May cause HDFN from transplacental passage of anti-D antibodies from Rh D negativewoman to an Rh D positive fetus1,resulting in potential fetal compromise or neonatal andlong-term morbidity0Generally no apparent adverse mate
